1. Field of the Invention
The present invention relates generally to earth-to-orbit transport systems and, more specifically, to booster recovery systems including deployable wings.
2. Description of the Related Art
Space shuttle solid rocket boosters are currently recovered by parachute systems. These systems have obvious limitations, one of which is that a water recovery is required.
Consideration has been given in the past to the use of fixed, clipped delta or straight wings. Fixed wing configurations, although depicted in studies, have not yet been accepted as a viable recovery system for twin boosters. A primary disadvantage is the difficulty encountered in integrating twin boosters with any type of fixed wing with the orbiter. Any single booster with non-stowable wings must, of necessity, be offset. This offset results in higher loads on both booster and orbiter wings because of the adverse relationship between engine thrust and launch system center of gravity, thus necessitating flight at higher than normal angles of attack. Also, the large bow shock wave off of a booster may impinge on the orbiter wing, or visa versa, making it necessary to make the wing even stronger.
Another disadvantage of clipped delta wings for twin boosters is that, even when stowed by hinging them at the wing root, the frontal area is much greater than a high aspect ratio oblique wing stowed with the span dimension along the longitudinal axis of the booster.
U.S. Pat. No. 4,834,324 describes a multiconfiguration reusable space transport system in which a pivoting panel acts as a heat shield in a stowed position and as a wing in the unstowed position for recovery of a first stage unit. The first stage unit corresponds to the present space shuttle external tank. The wing is rotatable between two positions. During launch, the wing is positioned in alignment with the longitudinal axis of the first stage unit and is flush with the flat base of the body. During flight for returning to earth, the wing extends perpendicular to the unit axis to permit horizontal landing.
A problem with U.S. Pat. No. 4,834,324 is that the pivoting panel has high planform loadings (defined by entry weight divided by the entry plan form area), and there is no adequate provision for a mechanism to deploy the wing.